Lubricating oils



' jcelerated wear and eventual engine failure.

Patented May 11, 1948 Bert 11. Lincoln, Ponca City, on... Gordon D. Byrklt, Niagara Falls, N. Y., and Waldo L.

Steiner, Ponca City, Okla asslgnors to Continental Oil Company, Ponca poration of Delaware Application November 9, 1942, Serial No. 465,094

20 Claims. (Cl. 252-46.6)

No Drawing.

This application is a continuation-in-part of our copending application Serial No. 283,570, filed July 10, 1939, which has since issued into Patent No. 2,348,080, dated May ,2, 1944.

Our invention relates to lubricating oils and more particularly to an improved lubricating oil of general utility which has a high film strength, is noncorrosive to the crankcase bearing materials and does not readily oxidize or form sludges and lacquers.-

In the development of new automotive and other type engines, increased power, higher oil temperature, increased bearing pressures per unit area, and other innovations have led to the installation of bearings made of new bearing materials, alloys and mixtures, which unfortunately are more readily attacked by oxidation products formed in the lubricant than 'was the old Bab-" bitt bearing metal. Some of these newer bearing materials are cadmium-silver, copper-lead, and alloys of lead with other metals. These metals are corroded readily by oils which have been used for a relatively short time in the engine. Oils which have been solvent refined or otherwise refined to produce oils with high viscosity indexes (for example, 93 V. I. or higher) are characterized by a deficiency of natural oxidation inhibitors and consequently are especially subject to oxidation which forms corrosive organic acids and prooxidation catalysts which promote the further oxidation and deterioration of the oil. These oils also have an objectionable characteristic in that they tend to deposit lacquerous formations upon the various engine parts, particularly the piston ring, ring grooves, and skirt. Ring sticking, poor heat radiation, and reduced lubrication cause ac- One method of overcoming the injurious bearing composition loss caused by corrosion would be to use more resistant bearing compositions and another would be to use an oil which does not develop these corrosive materials during use. Still another method would be to use a lubricant containing a material which would react with and render inert the oxidation products which promote oil deterioration and oxidation as rapidly as they are formed. Lacquer formation with the resultant ring-sticking, failure of proper radiation of heat with the resultant piston and cylinder wall warping, cylinder wall scumng, piston slap, etc., may often be prevented or reduced by adding a compound having that characteristic known as detergency. Such detergency compounds are metal organic compounds such as metal soaps, a metallo-organic compound, or a phosphorus compound to the oil.

City, 0kla.,a cor- Various addends have also been proposed for addition to lubricants for the purpose of inhibiting the formation of oxidation products during use. These may be called antioxidants, since they increase the induction period or that period of time before which oxidation begins and decrease the rate of oxidation after it has started.

Other organic compounds have been added to a lubricating oil to increase the film strength of the oil, thus allowing smaller bearing areas to support the same or heavier loads without the danger of the oil being squeezed from between the rubbing surfaces. These compounds are especially necessary in lubricating the modern hypoid gears and have proved to be very beneficial when used in the crankcases of high-powered internal combustion engines.

Our invention is not concerned with the first mentioned methods of reducing bearing metal loss, that is, use of more resistant bearing metals and the use of noncorrosive and nonoxidizing oil, but is concerned with the other methods of improving a lubricant.

The present invention proposes the addition of two addends to a lubricant which has been found to give the lubricant an unexpectedly superior activity in respect to film strength, corrosion inhibition, and lacquer prevention over what would be expected from simply the postulated eifect of the combination upon a lubricant from a knowledge of the effect of each of the addends used separately upon the oil.

Certain compounds when added to oils are physically or chemically held by, or otherwise combined with metals, forming tenacious films on the surface of the metals which enable them to withstand higher pressures without the welding of one metal surface to the other. The various chlorine and sulfur compounds are the most noteworthy of this type of compound and because of their activity are known as extreme pressure and mild extreme pressure addition agents.

Furthermore X-ray diffraction methods have shown that compounds having highly polar molecules, that is, molecules of unsymmetrical character containing an atom or group of atoms exhibiting a secondary or residual valence, tend to produce regimentation of the polarized molecules in a hydrocarbon oil upon the surface of metals immersed inthe oil. The coefflcient of friction of the oil is reduced by the orientation of the molecules. An oil exhibiting a low coefficient of friction for the viscosity thereof is known as an oil having a high oiliness factor.

One object of our invention is to provide a substantially noncorrosive lubricant for use with the new, easily corroded bearing compositions. It

is to be noted, however, that the improved lubricants here described are advantageously employed with all types of bearings, since they are less corrosive during use with any of the metals commonly encountered in practice and have properties apart from noncorrosiveness which designate them of great utility for many lubrication purposes.

Another object of the invention is to provide a lubricant inhibited against oxidation during use.v

via blow-by, etc., become a contaminant of the I lubricant.

Another object of the invention is to provide a lubricant which will not form undesirable lacquer and varnish coatings upon various parts of the piston and the parts of the engine cooperating therewith as readily as such deposits are formed by the refined mineral lubricating oils.

Another object of the invention is to provide a lubricant characterized by its ability to maintain sludge, polymerization products, and insoluble contaminants in a state of colloidal suspension as distinguished from sludge or insoluble .contaminants precipitated or deposited on the various parts of the engine.

Another object of our invention is to provide a lubricant of high oiliness characteristics.

Other objects of our invention will be apparent in the following description.

Our invention comprises an improved lubricating composition of especial utility for the lubrication of the bearing and frictioning surfaces of modern internal combustion engines, although, as noted above, it is not limited to such specific use. The lubricating composition comprises an oil of lubricating viscosity and two additives of unrelated properties which coact with the oil and each other to give a lubricating composition of superlative characteristics with respect to the most important properties of a lubricant to be used in the crankcase of an internal combustion engine.

One of the compounds of the invention is a sulfurized relatively high molecular weight olefin, the olefin being selected from the group of unsaturated organic compounds consisting of naturally occurring unsaturated mineral oils, vegetable oils, and animal oils, and the esters of their fatty acids, and manufactured oils, such as dehydrogenated oils, halogenated and dehydrohalogenated oils, cracked hydrocarbons, and similar olefins. More particularly the compound may be sulfurized corn oil, sulfurized cottonseed oil, sulfurized rapeseed oil, sulfurized castor' oil, sulfurized lard oil, sulfurized sperm oil, and the sulfurized esters of their fatty acids, sulfurized cracked wax, sulfurized cracked gasoline, sulfurized olefin obtained from narrow-cut liquid petroleum fractions, such as kerosene, gas oil, neutral oil, etc., or sulfurized olefin obtained by halogenating and dehydrohalogenating a petroleum wax.

The preferred compound is the suifurized olefin obtained by halogenating a petroleum wax whose monochloro derivative melts at a lower temperature than does the hydrocarbon itself, separating respectively the monochloro, dichloro, and more highly chlorinated derivatives from the unchlorinated wax and from the less highly chlorinated and more highly chlorinated hydrocarbons, dehydrohalogenating the relatively pure monochloro wax derivative or the dichloro wax derivative to obtain a relatively pure, homogeneous olefin. The sulfurization of the olefin is by means of a sulfurizing agent which may be elemental sulfur or a sulfur compound such as sulfur chloride, etc. This particular compound and the method of making the same are fully described in the United States Patent No. 2,218,032, issued October 5, 1940, upon the application of Bert H. Lincoln, Waldo L. Steiner, and Gordon D. Byrkit, Serial No, 205,531, filed May 2, 1938.

The other compound to be added to the lubricant is selected from the broad group of organic phosphorus compounds and may, in general, be any organic phosphorus compound having a slitficiently high boiling point to allow its incorporation and maintenance in a lubricant to be subjected to the heat conditions present in the crankcase of an internal combustion engine. It has been found that all phosphorus-containing organic compounds of sufiicient boiling point under atmospheric pressure to insure their continued presence in a lubricant enhance the activity of the suliurized olefin in the lubricant and in other respects produce a lubricant of improved quality. The phosphorus compounds may be broadly any organic phosphorus compound, and the phosphorus may be in its trivalent or pentavalent form; the .phosphorus compound may consist only of phosphorus, hydrogen, and carbon or it may contain in addition thereto an element or elements from the group consisting of oxygen, sulfur, tellurium, selenium, nitrogen, chlorine, and metals such as calcium, sodium, barium, tin, lead, zinc, aluminum, antimony, arsenic, lithium, etc. The phosphorus compound may be an ester of an acid of phosphorus or a compound having the phosphorus directly attached to one or more carbon atoms. The organic radical or radicals of the compound may be aliphatic, aromatic, heterocyclic, saturated, or unsaturated. In general, we have found that any organic compound characterized by the presence therein of phosphorus may be advantageously used in the practice of this invention. Particular classes and compounds within the broad class of organic phosphorus compounds are more effective addition agents for our purposes than are other organic phosphorus compounds; however all of the compounds are of some utility in the practice of our invention.

By the combination of the two additives, the oil fortified therewith is improved more than would be expected from the study of the efiect of the oil plus sulfurized olefin and an oil plus an organic phosphorus compound. The unexpected improvement will become apparent during the course of the following description.

As little as 0.05 per cent of the combination of the sulfur compounds and organic phosphorus compounds may be added to a lubricant with beneficial results therefrom in respect to resistance to oxidation, reduction in corrosiveness, and capability to maintain insoluble material in a state of colloidal suspension and in other important respects. zAsrmuch as 20 per cent of the combination of suliurized olefins and organic I phosphorus compounds may be added to a lubricant to obtain alubricant exhibiting markedly increased film strength, oiliness properties, prevention of sludges and lacquer-like varnish deposits, and resistance to oxidation and deterioration. It is seldom, however, that more than 2 per cent need be used for a crankcase lubricant. A lubricant containing from 2 to 20 per cent makes an admirable cutting oil or an extreme pressure lubricant.

THE Sunrua COMPOUND As above stated, relatively high molecular weight sulfur compounds suitable for the practice of this invention may be obtained by sulfurizing naturally occurring hydrocarbon olefins which may be an animal oil, such as sperm oil, lard oil; a semi-drying or non-drying ,vegetable fact a crude mixture containing as much as'7.2

oil, such as -corn oil,- castor oil, cottonseed oil,

rapeseed oil, palm oil, soya bean oil, etc., or the esters of their unsaturated fatty acids or by sulfurizing olefins produced by treating naturally occurring waxes, relatively pure high molecular weight parafiinic substances, narrow-cut liquid petroleum fractions, and petroleum wax, the treating being dehydrogenation, cracking, or halogenation and dehydrohalogenation. All of these sulfurized olefins have been added to lubricating compositions to improve the oils resistance to oxidation or to reduce thecorrosiveness of the oil which is subjected to oxidizing conditions. The most efi'icacious compound so far discovered for most purposes is the relatively pure sulfurized olefin obtained from petroleum wax by halogenation, separation, and dehydrohalogenation. The

preparation of this compound is described in the United States Patent No. 2,218,132, mentioned above. The narrow-cut liquid petroleum fraction such as Stoddards solvent, 9, narrow cut of kerosene, a narrow cut of distillate, a narrow cut gas oil, a narrow cut of gasoline, a narrow cut of a highly solvent-treated low (neutral) or high (bright stock) viscosity oil, etc., may be treated in the same manner, that is, by halogenation, separation, and dehydrohalogenation, to produce an olefin suitable for sulfurization and use in our invention.

In order to fully describe the sulfur compound, the method of preparation of the preferred sulfurized petroleum wax, having about 18 to 24 and the mono-, di-, and polychloro derivatives and cannot be considered the desired compounds. For example, a so-called trichloro paraffln wax containing 24 per cent chlorine, which corresponds very closely to percentages of chlorine in the trichloro compound, was separated by means of crystallization from acetone, the first (least soluble) portion consisting'of a mixture of monochloro wax and unchlorinated wax. The percentage of unchlorinated wax in the original mixture was found to be 7.2 per centythus even a trichloro paramn as so called in the prior We have found that these materials per cent of unchlorinated wax, and more highly chlorinated waxes. Its use would not give the homogeneous sulfurized products that are obtained from a relatively pure homogeneously halogenated paraflin wax.

As stated above, the relatively pure monoor diolefln free from unchlorinated hydrocarbons and free from more highly chlorinated hydrocarbons may be prepared by halogenation, separation, and dehydrohalogenation.

To produce a maximum amount of monochloro wax, about 10 per cent of chlorine is added to the petroleum wax having from 18 to 24 carbon atoms and a melting point of approximately 120 F. The other halogens may be used in place of the chlorine, but we prefer chlorine because of its availability and cheapness. As stated above, the chlorinated mass will contain unchlorinated wax. The chlorination of wax varies its melting point stepwise inversely as the degree of chlorination. The monochloro wax melts lower, than the unchlorinated wax. The dichlorinated wax melts lower than the monochlorinatedwax. By making use of this difference in melting points or differences in solubility, it is possible to separate readily the unchlorinated wax from the crude chlorination mixture, using sweating or selective solvent treating at various temperatures. Then the monochloro wax may be separated from the mixture of monochloro and more highly chlorinated wax in the same manner. We thus obtain a relatively pure monochloro wax of from 18 to 24 carbon atoms. If it is desired to produce a, maximum amount of a diolefln of from 18 to 24 carbon atoms, the process is carried out in the same manner except that 17 per cent chlorine is originally introduced into the wax, and the dichloro wax is separated from the unchlorinated, monochlorinated, and the more highly chlorinated wax.

A solution of the crude-chlorination mixture of chlorinated parailln wax may be formed with acetone. At about 70 F. the chlorinated waxes will be in solution while the unchlorinated wax will not be dissolved and may be separated out by settling, centrifuging, or filtering; The solution may be chilled to precipitate the monochloro wax. Thus the monochloro wax may be sepa-' rated from the polychloro wax, employing the same methods outlined for separating the unchlorinatedwax from the chlorinated wax mixture.

The monochloro wax thus obtained is substantially a pure monochloro compound, being free from unchlorinated and more highly chlorinated waxesalthough, of course, the homologues of from 18 to 24 carbon atoms are present and may be converted to the corresponding mono-olefin by removing the chlorine, along with an adjacent hydrogen, as hydrogen chloride, .thus producing a mono-olefin, To efiect dehydrohalogenation and thus produce the olefin, the monochloro wax may be heated for a period of a minute or less to five hourswith s of its weight, more or less of lime, at a temperature of from 200 F, to 500 F. A much lower percentage of lime or other basic material may be employed, although in many cases the higher percentages have been found to give a, better colored olefin composition. The olefin may be formed by heating with no basic or other material: however this is not recommended because of the darkened color of the product. This step is defined herein and in the claims as dehydrohalogenation, because the chlo.

form.

rine is removed, together with an atom of hydrogen from a carbon atom adjacent to the carbon atom to which the chlorine was attached. in the form of hydrochloric acid.

As mentioned before, it is possible to employ a relatively pure diolefin obtained from petroleum wax or a narrow-cut petroleum fraction in place of the mono-olefin. Instead of chloriuating to the theoretical chlorine content of a mono-olefin,

' the chlorination is carried on to the degree at r elemental sulfur or a sulfur compound such as a sulfur chloride, a phosphorus sulfide, or the like. In general, the sulfurized olefins prepared by reacting the olefins with a sulfur compound are more stable than the sulfurized olefins obtained by sulfurizing an olefin with elementary sulfur; however bycontrolling the temperature and time of reaction and diluent, it is possible to obtain stably bound sulfurized olefins by reacting the olefins with elemental sulfur.

It is to be understood that we do not intend to be limited to the particular sulfurized compound obtained from petroleum wax simply because it is a preferred example of our sulfur compounds. The other petroleum fractions and the animal and vegetable oils and esters of their fatty acids mentioned above are admirably suited for treatment in accordance with the above teaching to give sulfur-bearing compounds which are very effective materials when used in the practice of this invention.

Tm: Pnosrnonus Comrormns We have found that in general any organic phosphorus compound may be used in the pracphosphorus compound and the oil to which it is added. Higher percentages than this, however, may be desirable in particular cases. The organic phosphorus compound, if it is to be added to a lubricant to be employed in the crankcase of an .internal combustion engine, must be sufficiently stable to resist decomposition under conditions present in such a place and it must have a sufliciently high boiling point to prevent its volatilizing and being thus removed from the lubricating composition. Those phosphorus compounds having a vapor pressure of less than atmospheric at 170 F. are satisfactory for all ordinary purposes; and, for some purposes, those having a vapor pressure greater than atmospheric at even lower temperatures are operable.

As stated above, the organic phosphorus compounds may be any organic compound containing phosphorus in its trivalent or pentavalent The compound may consist entirely of phosphorus, hydrogen, and carbon, or it may (preferably) contain, in addition to carbon phosv phorus, and hydrogen, elements such as oxygen.

sulfur, tellurlum, selenium, nitrogen, chlorine, and metals such as calcium, sodium, barium, tin. lead, zinc, aluminum, antimony, arsenic, lithium, etc. The compound may be a straight ester or mixed ester of an acid of phosphorus and an organic compound which may be aliphatic, carbocyclic, or heterocyclic and which may he saturated or unsaturated. The phosphorus may be joined directly to carbon atoms of the organic radicals or it may be indirectly joined thereto through oxygen, sulfur, and other atoms. The organic phosphorus compound may be the product of the reaction of an organic compound such as a hydrocarbon, or a derivative thereof such as an alcohol, ketone, ester, and ether, in which the compound may be aliphatic or carbocyclic, and an inorganic phosphorus compound such as phosphorus trioxide, phosphorus pentoxide, phosphorus trisulfide, phosphorus pentasulfide, and yellow phosphorus. Compounds containing chlorine are especially effective. In general, we have determined that any organic compound characterized by the presence therein of one or more atoms of phosphorus may be utilized in the practice of this invention; and our invention, therefore, contemplates and environs the use of any such compound.

The following list of organic phosphorus compounds sets forth but a partial list of compounds which may be added to a lubricant in conjunction with a sulfurized olefin to improve the lubricant in respect to very important characteristics normally inadequate in the highly refined and moderately highly refined lubricating oil. This list of compounds is not to be considered a limitation of our invention but is only to be considered as a list of preferred examples of phosphorus compounds and further as representatives of the broad class of organic phosphorus compounds which, as we have indicated above, are effective lubricant additionagents when used for that purpose in conjunction with sulfurized olefins.

ORGANIC Pnosrnoaos COMPOUNDS I. Aliphatic Butyl phosphite Amyl phosphite Trimethyl phosphine oxide Trimethyl phosphine sulfide Triethyl phosphine oxide Triethyl phosphine sulfide Tripropyl phosphine oxide Tripropyl phosphine sulfide Tributyl phosphite Lecithin Diethyl isoamyl thiophosphinite Diamyl methyl phosphinite Diethyl propyl phosphinite Amyl diamylphosphinite Dibutyl alpha hydroxy isopropylphosphinate Tri (sulfurized oleyl alcohol) phosphite Ti'i (sulfurized oleyl alcohol) phosphate Trilauryl phosphite Trilauryl phosphate Trilauryl thiophosphite Trilauryl thiophosphate Trioctadecyl phosphite Trioctadecyl phosphate Trichlorolauryl phosphite Trichlorolauryl phosphate Calcium lauryl phosphite Aluminum lauryl phosphite Zinc lauryl phosphate II. Aromatic Triphenyl phosphine oxide Triphenyl phosphine sulfide Tritolyl phosphine oxide Tritolyl phosphine sulfide Trixylyl phosphine oxide Trixylyl phosphine sulfide Naphthyl phosphine oxide Naphthyl phosphine sulfide Trifurfuryl thiopho phite Trifurfuryl thiophosphate Monoethyl ditolyl phosphine oxide Monoethyl ditolyl phosphine sulfide Trifi'ryl phosphine oxide Triinryl phosphine sulfide Chlorotritolyl phosphine oxide Chlorotritolyl phosphine sulfide Phosphenyl oxide Phosphine-benzene Triphenyl phosphine Triphenyl phosphite Tritertiary amyl phenyl phosphite Tricresyl phosphite Tribeta naphthyl phosphite Tritertiary butyl phosphite Phenyl 1,4 phosphoxane Diethyl phenylphosphinite Diethyl phenyl thiophosphinite Isopropyl diphenylthiophosphinite Phenyl diphenylphosphinite Diethyl paratolylphosphinate Triph'enyl phosphine sulfide Triphenyl phosphine oxide P-carboxy phenyl phosphine oxide Propyl benzene dichlor phosphine. Butyl benzene dichlor phosphine B-amyl phenoxyethyl phosphite Triamyl phenyl phosphite Trichloro cresyl phosphite Tricresyl phosphate Tricresyl thiophosphite Tricresyl thiophosphate Sodium dicresyl phosphite Sodium dicresyl phosphate Aluminum phenyl thiophosphite Aluminum phenyl thiophosphate III. Carbocyclic Tricyclohexyl phosphite Tricyclohexyl phosphate Trichlorocyclohexyl phosphite Trichlorocyclohexyl phosphate Tricyclohexyl phosphine oxide Tricyclohexyl phosphine sulfide Tetrahydronaphthyl phosphine oxide Tetrahydronaphthyl phosphine sulfide Cyclo-tetramethylene methyl phosphine Cyclo-pentamethylene phosphine IV. Reaction products 1. Phosphorized rapeseed oil, formed .by reacting rapeseed oil with a reactant selected from the group consisting of phosphorus chlorides, phosphorus oxyhalides, phosphorus oxides, phosphorus sulfides, sodium phosphide and tin phosphide.

2. Phosphorized castor oil, formed by reacting castor oil with a reactant selected from the group consisting of phosphorus chlorides, phosphorus oxyhalides, phosphorus oxides, phosphorus sulfides, sodium phosphide, and tin phosphide.

3. Phosphorized hydrocarbon 011 made by reacting hydrocarbon oil with PSCla.

tartrate with phosphorus trichloride. v Reaction product formed by reacting phos- Reaction product of phosphorus trichloride with parafiin wax.

Reaction product of phosphorus pentoxide with cetyl alcohol. 1 Reaction product of phosphorus trisul do with octadecanol.

Lubricants having added thereto small but effective proportions of both a sulfurizedolefin and an organic'phosphorus compound possess unexpectedly superiorproperties. Highly refined lubricants such as solvent-treated Mid- Continent oils having a. viscosity index above 93 and Pennsylvania paraflinic oils normally quite corrosive to sensitive bearing metals after a short period of use are rendered stable and non corrosive by the remarkable antioxidant and inhibiting efiect of the combination of addition agents. Furthermore these same oils which are notoriously quick to form lacquers and varnishes on the highly heated metal surfaces contacted by them are rendered practically neutral in respect to formations of lacquer and varnish deposits. The most astonishing feature of this invention, however, is the extent to which the oil inhibited by the combination of inhibitors resists the formation of sludge and sludge-like materials commonly called naphtha and chloroform insolubles even-though the oil is used or tested under the most severe and accelerated oxidation conditions. This particular attribute is clearly shown in the modified Underwood tests hereinbelow discussed and in engine tests conducted on oils within the scope of this invention. Furthermore the lubricants of our invention maintain the insoluble constituents and contaminants normally present in a lubricating oil after usage colloidally suspended or in a, state other than that deposited on the engine parts in hard, gummy, or varnish-like deposits. For these reasons, the lubricants improved in accordance with this invention are of extraordinary value for the lubrication of the parts within the crankcases of internal combustion engines.

The foregoing facts were determined by various test procedures which have been devised and are available by which a comparative evaluation of oils with respect to deterioration thereof in service may be obtained in a relatively short period of time. The evidence of the-broad utility of inhibitors according to the invention in its intended field of service is afforded by the results of a test method wherein internal combustion engine lubricants comprise the oil environment in which the inhibitors function. This test is one devised in recent years to demonstrate the tendency of motor oils to deteriorate per se and their tendency to corrode bearing surfaces in internal combustion engines wherein the bearings are formed of or surfaced with easily corroded alloys. It is observed that motor oils derived from selected crudes predominantly parafiinic in origin, as well as other oils from other crudes which have been improved by treatment with selective solvents,

. Reaction: product formed by reacting dibutyl phorus trichloride with trimethyl citrate.

exhibit a marked tendency toward corrosion oi the bearings in question, although in other respects the lubricants are of superior quality. The test, which is known as the "modified Underwood oxidation test, is conducted substantially as follows:

Standard half-bearings of copper-lead and cadmium-silver are supported in a chamber through which air may be circulated. A sheet of lead is placed in the heater chamber. This acts as a catalyst to promote andincrease the rate of oxidation and deterioration of the oil. The surfaces of the bearings are exposed for various periods of time to a stream of oil sprayed under pressure continuously upon the corrodiblo areas. The oil is maintained at a temperature of 350 F. The oil is recirculated over the bearing surfaces to simulate surface conditions in an automotive crankcase. The oil deterioration is ascertained by determining the neutralization number of the oil after a test run as'well as other physical and chemical changes such as the increase of viscosity, the carbon residue, and the resin and sludge content. The measureof corrosion is taken as the loss in welghtoi the bearings per unit of exposed corrodible surface.

The foregoing test, which has been determined to be very well correlated with actual crankcase service conditions, was made upon unblended oils, blends of oil with suliurized oleflns, blends of oil with organic phosphorus compounds, and blends of oil with combinations oi sulfurized olefin and various organic phosphorus compounds.

The results of these tests clearly revealed the properties and advantages of lubricants prepared according to this invention, particularly if the lubricant is to be used in the crankcase oi an internal combustion engine.

Tm: Momrnm Ummnwoon Tns'rs An unblended 400 pale. oil solvent treated to a. viscosity index or 98 by treating with 3 parts furfural to 1 part oil at 250 F. and having a Saybolt universal viscosity of 61.0 seconds at 210 F. was tested in the modified Underwood oxidation apparatus. The following determinations were ma e:

Test 1.-Blank oil, unblended 400 pale Test 2.--0il plus 0.015% sulfur in the form of sulfur-Iced olefin Hours 12 l 14 i6 18 Corrosion Cu-Pb Gms ..L 0. 0o 0. as 1.17 1. Corrosion Cd-Ag Gms 1.27 2. 05 z. 93 4. 54 Neutralization No 8. 1 l0. 5 10. 8 l0. 5 Petroleum Naphtha Insoluble, per

cent by weight 0. 10 0. i4 0. 08 0. 08 hloroform Insoluble, per cont 0.08 0. 12 0.06 0. 06 Viscosity, Seconds Saybolt, 210 F.

l. 86. 3 102. 8 119. 4 136. 3 Carbon Residue, per cent... 2. 2 3. 3 4. 6 6. 0 Resin, per cent 19. 72 21. 74 27. 36 30. 87

The test reveals that this oil was much better than the unblended oil, no copper-lead corrosion having occurred until after nearly 14 hours; however the cadmium-silver half-bearing was badly corroded in 12 hours, and the acid content of the oil was high. The viscosity oi! the oil had been increased by use to such an extent that after 18 hours it was 75.1 seconds Saybolt more viscous at 210 F. than was the original oil. The resin content of the oil was also high.

A sample of the same 011 as was tested in Test 1 and used as the base oil in Test 2 was blended with 0.5 per cent triphenyl phosphite. The following determinations were made:

Test 3.--Ozl plus 0.5% triphenul phosphite Hours 10% I 13% l 16% I 19% Corrosion Cu-Pb Gms.- 0.00 0.00 0. i4 0. 42 Corrosion Cd-Ag Gms 0. 00 0. 00 1.01 2. 36 Neutralization N o 0. 5 0. 8 5.0 6. 0 Petroleum Naphtha Insoluble, per

cent by weight 0.02 0. 03 0.03 0. 03 Chloroiorn'i Insoluble, per cent 0. 02 0.03 0. 03 0.03 Viscosity, Seconds Saybolt 210 F.

1.0) .8 62. 6 87. 7 132. 4 Carbon Residue, per cent. 0.14 0.23 1. 21 2. 69 Resin, per cent 2. 9i) 3. 85 21. 35 32. 48

The test indicates that this oil is greatly improved as compared to the unblended oil in that no corrosionhad occurred at 13 hours; however at 16 hours the oil had seriously deteriorated to the point where it was very corrosive to cadmium-silver alloys and quite corrosive to copper-lead alloys, the acid content or the oil'having risen to an alarming ratio; and the resin content was very high.

A sample of oil, the same as used in Test 1 and as base stock for the oils tested in Tests 2 Home 2 3 4 5 and 3, was blended with 0.015 per cent sulfur in the form or sulfurized olefin in which the olefin was obtained by halogenating and dehydrohaloo i 0 -Ph 0 gg flg gfi 33. 15 32 32 2% 222 gig genating paramn wax and 0.5 per cent triphenyl on runs 0 3.1 5. Petroleum gn Insoluble, per 1 6 0 10 phosphite. The following determinations were cent by weight 0.06 0.03 0.08 0.09 60 madettiii'? $ietit *eis" #8 3% riii 12% e .ray Ramstbotton Carbon Residue, per 0 5 I 02 1 56 2 55 Test 4.Oil plus 0.015 per cent sulfur and 0.5

ccn Resin,per cent as 14.92 20.94 27.26 per cent phospmte Hours i0 15 20 l 25 It is apparent that thisoil failed rapidly, corrosion being under way at 2 hours with a heavy Corrosion Cu-Pb Gms 0.00 0.00 0.01 0.08 Cd-Ag loss after 5 hours and a viscosity increase ggggiggg ggfififi 92 9g O! 88.6 S. S. U. seconds 81081'5 hours. PetrotlegmwNiagzltha Insoluble, per 0 04 0 08 0 as y e 0.16 A Sample of the same on blended with Cl i l groiorm lnioluble, per cent 0.03 0.03 0.04 0.14 0.015 per cent sulfur in the form of sulfurized visc gitv. Se ssvbolt 21 61 4 63 0 64, 4 66 a fi t l fin havin een deriv d from P car bnietiiah','it?iiii "II 0:19 017 0. 15 0. '16 leum wax. The following determinations were B68111 made:

The examination of this oil proved it to be practically noncorrosive at 25 hours, only 0.08 gram of the copper-lead half-bearing having been lost and only 0.04 gram or the cadmiumsilver half-bearing having been lost. The acid content of the oil was relatively low. The carbon residue and resin content were very low. The viscosity of the oil was practically unaifected.

A study of the above results graphically reveals that we have accomplished the objects of our invention. We have produced a lubricant which may be used for unusually long periods of time under severe operating conditions in the crankcase 01' an internal combustion engine without danger of bearing loss through corrosion. We have made available a lubricant which is not readily oxidized to form sludges and lacquer formations. The lubricant prepared in accordance with our invention does not become viscous with use under severe conditions as does the lubricant which has not been blended with the additives which are within the ambit of this invention. The results obtained by the combination of the two classes of additives are unexpectedly greater and more beneficial than would be expected from the study of the effect of each of the additives added separately to oil. We have no adequate theory to explain this enhanced oil but believe the phosphorus compounds act as antioxidants to prevent the early oxidation and decomposition of the oil but that their effect is lost after a short time of severe operating useand also impart that characteristic above referred to as detergency to an oil while the sulfur compound is not a true antioxidant but only as anticorrosive properties by (a) reacting with the corrosive products of oxidation, corrosion, and decomposition to render them inert and (b) reacting with the catalytically active material such as metallic oxides and salts rendering them inert catalytically. We believe the combined eifect of the addition of small amounts of sulfurized olefins, prepared by halogenating and .dehalogenating narrow-cut petroleum fractions, and a small amount of an organic phosphorus compound -is to produce an oil stabilized against oxidation and deterioration for a loner period of time and further beneficially affected after it has started to oxidize and decompose by being maintained in a noncorrosive and catalytically inert condition therebyproducing an oil capable of use for prolonged periods of time under severe conditions without serious change in lubricating ability or damage to the readily corroded bearing metals. We do not intend to be bound by our theory but prefer to base our invention upon the improved effect which may be demonstrated.

Even though the joint action of the sulfur compound and phosphorus compound gives results unexpected from a combination of the actions of the two compounds separately, we have found that the ratio of phosphorus to sulfur in the finished lubricant should be fairly well controlled for most satisfactory results. Generally speaking, we prefer to use combinations of sul-furized compounds and organic phosphorus compounds in which at least 10 per cent but not more than '70 per cent of the combined weight of the additives is an organic phosphorus compound. This particular range, however, is notv critical; and smaller or larger proportions may be used and,

, ments, the lubricants prepared according. to this invention, especially those containing a relatively .portion of some of the organic phosphorus compounds exhibit increased detergency and peptizing character .and are of particular value for use in Diesel engine crankcases' where the'presence of soot and products of combustion constitutes a serious problem.

The lubricating oil portion of the blends of our invention may be so-called mineral or hydrocarbon oils which may be poorly, moderately, or highly refined, paraflinic or naphthenic, or may consist wholly of or contain only in part certain fatty oils, including corn oil, soy bean oil, lard oil, and like oils of lubricating viscosity. The blends may contain volatilized oils or synthetic oils of lubricating viscosity. Soap-thickened or otherwise thickened oils used as greases may be employed. Addends for other purposes such as a pour point depressant may be present.

Since the phosphorus compounds have varying degrees of solubility in various hydrocarbon oils in some cases, it may be necessary to use a mutual solvent for the compound and the oil in order to properly incorporate the phosphorus compound into the oil.

Finally and again it may be said that very small amounts of these compounds are very effective when added to a lubricating oil. A wide rangemay be employed. As little as 0.001 per cent of the combination of these compounds appreciably improves the oil. As much as 20 per cent of the combination of these compounds may be used in gear lubricants and the like.

It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without .departing from the spirit of our invention. It is therefore to be understood that our invention is not to be limited to the specific details shown and described.

Having thus described our invention, we claim:

1. A lubricant comprising in combination a major proportion of an oil of lubricating viscosity and a minor proportion, sufilcient to improve the properties of the oil as regards corrosion and oxidation of sulfurized monomeric olefin, said olefin being obtained from a narrow-cut petroleum fraction and a minor proportion of an organic phosphorus compound.

2. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being formed by halogenating and dehydrohalogenating petroleum wax, and an organic phosphorus compound.

3. A lubricant comprising in combination a.

major proportion of oil of lubricating viscosity and a minor amount, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being formed by halogenating a petroleum wax, separating the monochlor wax from the unchlorinated wax and the more highly chlorinated wax, and dehydrohalogenating the relatively pure monochlor wax, and a minor proportion. of an organic phosphorus compound.

4. A lubricant comprising in combination a -major proportion of oil of lubricating viscosity and a minor proportion, sufficient to improve the properties of the oil as regards corrosion and oxidation of a sulfurized olefin, said olefin being obtained by chlorinating a relatively pure petroleum wax to the monochlor compound, separating the monochlor wax from the crude-chlorination mixture and dehydrohalogenating, the sulfurizing being by means of an agent selected from the group consisting of elemental sulfur, chlorides of sulfur, sulfides of phosphorus, and a minor proportion of an organic phosphorus compound.

6. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suificient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being formed by chlorinating a, petroleum parafiin wax to the monochlor compound, separating the monochlor compound from the crude-chlorination mixture and dechlorinating by heating in the presence of a catalyst, the sulfurizing being by means of elemental sulfur, and a minor proportion of an organic phosphorus compound.

7. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a min-or proportion, suflicient to improve the properties of the oil as regards corrosion andoxidation of sulfurized olefin, said olefin being formed by chlorinating a petroleum wax to the monochlor wax, separating the monochlor wax from the crude-chlorination mixture, dechlorinating, the sulfurization being by means of a sulfur compound selected from the group consisting of sulfides of phosphorus and chlorides of sulfur, and a minor proportion of an organic phosphorus compound.

8. A lubricant comprising in combination a major proportion of oil of lubricating viscosity, a, minor proportion, suflicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by chlorinating a paraflin wax, and dechlorinating, and a minor proportion of an aliphatic phosphorus compound.

9. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufilcient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained from parafiln wax by halogenation and dehalogenation, and a minor proportion of an aromatic phosphorus compound.

11. A lubricant comprlsingin combination a major proportion of oil of lubricating viscosity and a minor proportion, sufilcient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained from petroleum wax by halogenation and dehalogenation, and a minor proportion of phosphorized mineraloil.

12. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained from petroleum wax by halogenation and. dehalogenation, and a minor proportion of ester of phosphorus acid.

13. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating and dehalogenating paraflln wax, and a minor proportion of a phosphine.

14. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating and dehalogenating parafiin wax, and a minor proportion of an or- 10. A lubricant comprising in combination a major proportion of lubricating oil and a minor proportion, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating a paraflin wax and dehalogenating, and a minor proportion of heterocyclic phosphorus'compound.

ganic phosphate."

15. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufficient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating and dehalogenating paraffin wax, and a minor proportion of an organic phosphite.

16. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating and dehalogenating parafiin wax, and a minor proportion of triphenyl phosphite.

17. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, suflicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating and dehalogenating paraffin wax, and a minor proportion of triethyl phosphine oxide.

18. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized olefin, said olefin being obtained by halogenating and dehalogenating paraffin wax, and a minor proportion of lecithin.

19. A lubricant comprising in combination a major proportion of oil of lubricating viscosity and a minor proportion, sufiicient to improve the properties of the oil as regards corrosion and oxidation of sulfurized relatively high molecular weight olefin and a minor proportion of an or 17 being obtained from petroleum. and a minor proportion of an organic phosphorus compound.

BERT H. LINCOLN. GORDON D. BYRKIT. WALDO L. SfrEINER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,167,867 Benning Ant. 1, 1939 Number 

